I have seen them and they have such a high color temperature that it is strainful to the eyes for prolonged periods of reading. Same as with most CFLs.
I bought some of the LED Christmas lights, and we had to move them outside because looking at them made everyone sick.
But I know what you're talking about. IIRC, it's the lack of "red" spectrum that causes the eye strain. My reading CFL is pretty warm.
My LED flashlights aren't that great for detail work, either.